Diabetes, pollution linked to faster brain ageing: Study

A new study found that specific parts of the brain are most vulnerable to diabetes, traffic-related air pollution, and alcohol, of all the common risk factors for dementia. As these are modifiable risk factors, the findings emphasise the need to address them.

In a previous study, researchers from the University of Oxford had identified a ‘weak spot’ in the brain, which refers to a specific network of higher-order regions that develop during adolescence and also show earlier degeneration in old age. In the new study the researchers examined the genetic and modifiable influences on fragile brain regions by looking at the brain scans of 40,000 UK Biobank participants aged over 45, the university’s press statement revealed.

The researchers examined 161 risk factors for dementia and ranked them according to how they affected the ‘weak spot’ beyond the natural effects of age. These ‘modifiable’ risk factors, which can be changed to reduce dementia risk, were sorted into 15 categories: blood pressure, cholesterol, diabetes, weight, alcohol consumption, smoking, depressive mood, inflammation, pollution, hearing, sleep, socialisation, diet, physical activity, and education.

A comprehensive analysis showed that after considering the effects of age and sex, the three factors that emerged as the most harmful risk factors for dementia were diabetes, air pollution, and alcohol, the statement explained. 

“What makes this study special is that we examined the unique contribution of each modifiable risk factor by looking at all of them together to assess the resulting degeneration of this particular brain ‘weak spot’,” co-author Anderson Winkler said in the statement.

The findings, published in Nature Communications, showed that while genetic predispositions play a role in dementia risk, the potential modifiability of many risk factors is a reminder of the importance of public health policies and actions.

One of the important findings of the study was how air pollution is a risk factor for dementia, which highlights how crucial the environment people live in is for their health. Previous studies have also shown a link between air pollution and dementia risk. For instance, an April 2023 study, published in the journal BMJ showed that long exposure to polluted air containing high levels of fine particles is linked to dementia.

Another study, published in the journal Neurology in February 2024, found that higher exposure to air pollution could be linked to high amounts of amyloid plaques in the brains which is associated with Alzheimer’s disease.